The nationwide US study, by the National Institute of Environmental Sciences, is the first to link ovarian cancer to the washing ritual.

The NHS advices women against douching entirely as it can also make them more susceptible to infections and inflammations.

Professor Ronnie Lamont, spokesperson for the Royal College of Obstetricians and Gynaecologists, writes on the NHS website: “The vagina contains more bacteria than anywhere else in the body after the bowel, but the bacteria are there for a reason.

“I can’t think of any circumstances where douches are helpful, because all they do is wash out everything that’s in the vagina, including all the healthy bacteria.”

Around 7,300 women are diagnosed with ovarian cancer every year in the UK but the survival rate is just 35%.

Prognosis is believed to be so bad because women often experience no symptoms until the disease has progressed to an advanced stage.